opált

Opált, also known as opal, is a mineraloid composed of hydrated silica (SiO2·nH2O). It is renowned for its vibrant play-of-color, a phenomenon caused by the diffraction of light within its microstructure of silica spheres. Opal occurs in a wide range of colors, including white, black, blue, green, orange, and red, making it highly valued for use in jewelry and ornamental objects.

Opals are found in sedimentary deposits and are formed through the gradual deposition of silica-rich solutions in voids and cavities within rocks. The most prolific sources of opal include Australia, which produces over 90% of the world’s supply, as well as countries like Ethiopia, Mexico, Brazil, and the United States.

There are several types of opal. Precious opal exhibits vivid play-of-color, while common opal, or "potch," lacks this iridescence. Fire opal, originating mainly from Mexico, features bright orange to red hues and may or may not display play-of-color. The value of opal is primarily determined by its color, clarity, pattern, and the intensity of its play-of-color.

Opal has been used by humans for thousands of years, dating back to ancient civilizations such as the Romans and Indigenous peoples of Australia. It is also believed to carry metaphysical properties, including enhancing creativity and emotional expression, although these claims lack scientific validation.

Due to its relative softness (wearing a 5.5 to 6 on the Mohs scale) and porosity, opal requires careful handling and protection against scratches and dehydration. Proper storage and cleaning enhance its appearance and longevity, preserving its unique optical effects.